JCox23

As the car ran before I had the heads pulled there was no sign of bad guides. After having the heads pulled and seeing the video that was sent to me from the builder, I came to the conclusion that with that much wiggle in the valves, it was in fact a ticking time bomb. I had no way of knowing that before hand. I was just stating it showed no signs but yet turned out to be very bad.

Hopefully that clears it up.

propain

I am curious because the "bounce" being questioned and dismissed is documented from a very specific spring and setup. So its difficult to simply the bounce inspection results without knowing if it was the same setup and we have seen with Katech's spintron results as seen here:




Let me know if you can come up with more info. Thanks!

JCox23

I will look tonight when I get home and get back to you!

8850

I believe that the indicator should be placed closer to the guide to more accurately read the valve stem to guide clearance. The top side of the head would be the correct position. Reading the valve OD and with the valve extended out from the head would read more than the actual clearance.

'06 Quicksilver Z06

Good information if you can get it.

At the very least, we know that "valve bounce" apparently did not adversely affect the heavier valves in your setup.

And I suspect that yours is not the only heavier than stock valve train in these cars whereby predicted valve bounce results in no practical, discernible, appreciable or real world issue.

Mark2009

No, we don't. Unless you have some metallurgical or other lab inspection results you'd like to share.

Dismissal of the laws of physics will not prevent one from becoming their victim.

Johnjan

+1

I'm amazed at the conclusions that are drawn from measurements that are not performed properly - and taken as gospel. If you're going to remove the heads, measure the clearance correctly (by subtracting the valve stem OD from the valve guide ID and THEN post the results.

This whole valve guide issue is beyond ridiculous and will remain so until people insist on discussing fact instead of folklore.

Despicable Z

And here we go

zcarbon

Does Barnes Noble sell a good Valve guide?

8850

Yep, and a go and no go pin gauge would actually be the preferred method with the heads off the car for measuring guide ID.

propain

Thanks again. The more info the better. Its not only the weight of the valve its how well the spring controls it. As you can see by the data (not words only) given by Katech the stock LS7 spring controls the bounce way better than the dual spring setup with the same heavy REV valve. To say that the long term results of such a difference are inconsequential is unreasonable. That is why I am interested in which spring you were running and how it was setup.

Also, valve bounce effects with such low miles will not become apparent anyhow. At least not to the naked eye.

propain

Please note where and how it began.

ctsv510

I don't see that in the results?

According to the test Katech made the recommendation that both setups are fine for a street car with a 7000 rpm redline. In fact the dual springs/Rev valves stayed more under control for most rpms above 6800 (except right at 7200) than the stock springs with the Rev valve:

http://forums.corvetteforum.com/c6-z...tte-forum.html

I think you are thinking of the PSI springs as tested with the Torquer cam. That is a different story, though stock LS7 springs were not a part of the test.

propain

I was speaking about the Cam results since JCox23 is running one. You are correct though on the LS7 spring. It was the PSI spring that tested way better over the dual spring with the cam and the REV valves.

ctsv510

Ok I thought I missed something. I don't recall reviewing that chart but I knew I read that thread. Must have been a while back.

'06 Quicksilver Z06

I said "apparently". Not "definitely".

That indicates that from what his shop observed and reported there is no "apparent" adverse affect on his valves.

Now if someone else wants to go any further in terms of scanning electron microscopy or other lab inspection, well then that's their prerogative.

But from what his shop reports, they saw no "apparent" adverse affect on his valves.


Which is why it's difficult for me to imagine how someone with severe valve guide wear would delay doing anything about it.

Good thing JCox23 acted as soon as he found out his guides were shot.

You're possibly right.

I asked a question that JCox23 was gracious enough to answer, and his answer casts doubt as to the practical concerns that prior predictions ought to play in one's decisions on the management of this matter.

The man answered that his heavier than stock valves didn't show any signs of ill effect due to valve bounce.

That is a key point for many of us who run non stock SS valves, and apparently was a key point for JCox himself, as he went to the effort to relay my question to his shop.

propain

Yeah, the colors are too damn close anyhow.

Both seem to be close and .001 or .002 before 6800 is negligible for either. After 6800 however the dual spring verse the LS7 spring with the heavy valve cant keep up with the OEM Beehive. Every day street driven looks fine though.

I wonder how well the PSI spring would perform with the stock cam and the REV valve.

MTIRC6Z

Same thing could be said of the OP's valve guides before the heads were pulled...a look and listen to his engine showed no "apparent" problems and we know how accurate that turned out to be

Some people will believe what they want to believe because it makes them feel better beyond any words that are available in the English language and the absence of any real proof cannot be a concern because it would take away from the euphoric feeling.

Cheers, Paul.

'06 Quicksilver Z06

Forgive me for not reading all of that Paul and just scanning it because I'm on this iPhone. So no offense, but while I'm sure that what you say above has some merit, I'll throw this out there. Might even tie in to what you say above.

Does anyone wonder what the reaction among some would have been had JCox23's shop told him that his Non stock exhaust valves were examined after that 3 years and found to be FUBARed, tuliped and the stems beat to hell due to valve bounce?

I'm thinking that some of our membership, would have been euphoric. Would have felt some vindication.

I think the issue here, is that some of us are "disappointed" that this wasn't the case on this particular instance, and because it wasn't, this, coupled with the outright lack of described failures in here due to "valve bounce", in cars running solid SS Valves or slightly heavier than stock exhaust valves, despite the predictions of disaster, casts doubt as to the concern, from a practical standpoint, which should be given to any such predictions.

If the guy had come back and said that his valves were shot, then some of the naysayers about setups such as his would have something to point to.

His exhaust valves not only were not shot or tuliped or showed any other damage, but were indeed felt to be in good enough shape to re use.

Basically, the "problem" for some of us here, if there is one, is that JCox23 gave the "wrong" answer.

I've heard cries for metallurgical and lab data with regard to his results and associated comments. Among people in general, it seems to me that whenever someone gives the answer that we don't want, then the tendency is to ask more questions, indeed a battery of questions in some instances, until the answer that we wanted to hear, or had our hearts set on and hinged our positions from, is obtained.

propain

So true Paul. We also see a lot of strawman arguments when the proof is asked for.